New anatomical information on Anomalocaris from the Cambrian Emu Bay Shale of South Australia and a reassessment of its inferred predatory habits

摘要: Two species of Anomalocaris co-occur in the Emu Bay Shale (Cambrian Series 2, Stage 4) at Big Gully, Kangaroo Island. Frontal appendages briggsi Nedin, 1995, are more common than those cf. canadensis Whiteaves, 1892, a quarry inland wave-cut platform site from which these were originally described. An oral cone has three large, node-bearing plates recently documented for canadensis, confirming that lacks tetraradial ‘Peytoia’ and strengthening case identity Australian specimens as Anomalocaris. Disarticulated anomalocaridid body flaps numerous other localities, they preserve anatomical details not recognized elsewhere. Transverse lines on anterior part flaps, interpreted rays or veins previous descriptions anomalocaridids, associated with internal structures consisting series well-bounded, striated blocks bars. Their structure is consistent structural function imparting strength to flaps. Setal lanceolate blades similar anomalocaridids found isolation A single specimen also preserves putative gut diverticula. The morphology appendages, cone, diverticula compound eyes Anomalocaris, along its large size, suggests it was an active predator, coprolites containing trilobite fragments trilobites prominent injuries have been cited evidence predation trilobites. Based frontal appendage morphology, inferred predator soft-bodied animals exclusively only may capable durophagous trilobites, although (including possible cannibalism) by Redlichia could explain damage exoskeletons Shale.